The Casey Saddle Hut burned down in October 2015. It is yet to be rebuilt.
Permit required - New Zealand has a unique system of simple (mostly) backcountry huts that typically have wood/coal heating stoves, plastic-covered mattresses, clean water and bunkhouse communal living. Space can be limited and permits are required.
Check in the LDOC offices of major towns for permits. Good information can be found here: doc.govt.nz/
This is an even trail with some rough, uneven sections. Be aware that there are some sections where you have to lower yourself on roots to descend.
The trail starts off with a vigorous climb that makes switchbacks up into the higher country for about 1.5 miles. From here, you slowly drop back down until you end up in a broad and grassy river plain.
For the next few miles, you stay down in the valley where you'll cross the stream a few times. Eventually, the valley narrows down and you head uphill on more switchbacks. In half a mile, the trail flattens out and you are on the 'Casey Saddle' for the next mile. The final mile of the trail is the most challenging, where you descend sharply, often using roots to lower yourself.